code: def test_substitute(self):
      audio, sampling_rate = AudioLoader.load_audio(
          self.sample_wav_file
      )
  
      aug = naa.ShiftAug(sampling_rate, duration=0.5)
      augmented_data = aug.augment(self.audio)
      augmented_audio = augmented_data[0]
  
      self.assertFalse(np.array_equal(audio, augmented_audio))
      self.assertTrue(len(audio), len(augmented_audio))
  
file_path: nlpaug/test/augmenter/audio/test_shift.py
imports: import unittest
  import os
  import numpy
  from dotenv import load_dotenv
  import nlpaug.augmenter.audio
  from nlpaug.util import AudioLoader
label_desc: Use image node_id 2 for calling the TestShift obj's underlying member method code with example usage: obj.test_substitute() without return types